1. Field of the Invention
This invention relates to dispensing, and more particularly to an improved manually actuated pump characterized as an accumulative pump having a high compression ratio for providing superior performance for pump a product from a container for discharge from a terminal orifice.
2. Background of the Invention
Hand operated pumps are being used to dispense a wide variety of products such as household, institutional and personal care products and the like. Typically, a hand operated pump comprised a body defining an internal pump cylinder for receiving a reciprocating piston slidably disposed within the internal pump cylinder for defining a pump chamber. The pump is secured to a container for receiving liquid from the container through an induction tube. A pump stem had a first and a second stem end with a stem passage extending therebetween. The first stem end of the stem cooperated with the piston slidably disposed within the internal pump cylinder whereas the second stem end supports an actuator having a terminal orifice.
A first one-way valve enabled the flow of the liquid from the container into the internal pump cylinder whereas a second one-way valve enables the flow of the liquid from the internal pump cylinder to the terminal orifice. A spring biased the piston and the pump stem into an extended position for enabling an operator to reciprocate the piston between the extended position to a retracted position for pumping the liquid from the internal pump cylinder for discharge from the terminal orifice.
In many cases, it was desirable to allow the air pressure within the pump chamber to accumulate prior to the opening of the second one-way valve. The accumulation of the air pressure within the pump chamber insured a sufficient pressure within the pump chamber prior to the opening of the second one-way valve to properly discharge the liquid from the terminal orifice. The accumulation of the air pressure within the pump chamber produced a more uniform spray pattern throughout the movement of the pump stem from the extended position to the retracted position. Furthermore, the accumulation of the air pressure within the pump chamber reduced any dribbling of the liquid product from the terminal orifice when the pump stem is proximate to the extended position or proximate to the retracted position. Mechanically actuated pumps that were characterized by accumulating air pressure within the pump chamber prior to opening of the second one-way valve were commonly referred to as accumulative pumps.
In order to configure a manually actuated pump to function as an accumulative pump, the second one-way valve were be designed to open only upon the establishment of a predetermined minimum pressure. This predetermined minimum pressure insured the second one-way valve would open only when there was adequate pressure within the pump chamber to properly discharge the liquid from the terminal orifice.
When a mechanical operated pump was first used, the mechanical operated pump had to be capable of removing the air within the pump chamber and to draw the liquid from the container into the pump chamber. This process was commonly referred to as priming the pump. Unfortunately, the mechanically operated pumps of the prior art could not generate a sufficient pressure within the pump chamber to equal or exceed the predetermined minimum pressure necessary to open the second one-way valve. Accordingly, various methods and were incorporated within the pumps of the prior art to insure the priming of the mechanically operated pumps of the prior art.
In many cases, the manually actuated pumps of the prior art primed the pump through the diptube through a lost motion between the piston and the pump stem. Other manually actuated pumps of the prior art primed the pump through a vent between the pump stem and a closure by breaking the seal of the pump chamber.
Another associated difficulty of the prior art accumulative pumps is the low pump chamber pressure generated by the prior art accumulative pumps. The low pump chamber pressure generated by the prior art accumulative pumps adversely affected the spray performance of the pump when dispensing certain liquid products.
A further associated difficulty of the prior art accumulative pumps is the low compression ratio of the prior art accumulative pumps. The low compression ratio of some prior art accumulative pumps limited the ability of the pump to dispense high viscosity liquids from the container. Accordingly, these low compression pumps of the prior art had a limited range of liquids that could be satisfactorily dispensed from the pump.
Although the aforementioned prior art pumps have contributed to the dispensing art, there is a need for a high performance high compression ratio pump capable of high performance dispensing of a wide variety of liquids having various viscosities.
Therefore, it is an object of the present invention to provide an improved manually actuated pump having the properties of an accumulative pump with a high compression ratio for enabling the pump to be primed through a terminal orifice.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that is capable of generating a high pump chamber pressure for providing superior spray performance.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that is capable of spraying a variety of liquid products.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that is capable of spraying a wide variety of liquid products having various viscosities.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that provide a high flow rate to the liquid product that is discharged from the pumps.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that incorporates a first and a second one-way valve wherein the second one-way valve provides a metering orifice for liquid product discharged from the terminal orifice.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that incorporates a first and a second one-way valve wherein the second one-way valve includes a valve projection for engaging with a surface when the piston is moved in proximity to a retracted position to open the second one-way valve for releasing compressed air within a pump chamber for priming the manually actuated pump.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that minimizes the construction material required fabricate the pump for making the pump economically advantageous over the pumps of the prior art.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that can be constructed of molded plastic parts with a minimum of mold cavities.
Another object of this invention is to provide an improved manually actuated pump having the properties of an accumulative pump that may be assembled on automatic assembly machines with a minimum of assembly operations.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention with in the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.